core-js/modules/es.array.index-of.js

'use strict';
var $ = require('../internals/export');
var $indexOf = require('../internals/array-includes').indexOf;
var arrayMethodIsStrict = require('../internals/array-method-is-strict');
var arrayMethodUsesToLength = require('../internals/array-method-uses-to-length');

var nativeIndexOf = [].indexOf;

var NEGATIVE_ZERO = !!nativeIndexOf && 1 / [1].indexOf(1, -0) < 0;
var STRICT_METHOD = arrayMethodIsStrict('indexOf');
var USES_TO_LENGTH = arrayMethodUsesToLength('indexOf', { ACCESSORS: true, 1: 0 });

// `Array.prototype.indexOf` method
// https://tc39.es/ecma262/#sec-array.prototype.indexof
$({ target: 'Array', proto: true, forced: NEGATIVE_ZERO || !STRICT_METHOD || !USES_TO_LENGTH }, {
  indexOf: function indexOf(searchElement /* , fromIndex = 0 */) {
    return NEGATIVE_ZERO
      // convert -0 to +0
      ? nativeIndexOf.apply(this, arguments) || 0
      : $indexOf(this, searchElement, arguments.length > 1 ? arguments[1] : undefined);
  }
});